Brake cooling my MX5
The Mazda MX5 Miata is a competent vehicle for track duty. With a well designed suspension, and numerous well known upgrades it is very easy and relatively cheap to get started as a track-day vehicle. Many professionals and amateurs alike use the MX5 Miata to race.
I purchased and have been using my 2007 MX5 for track days. Of all the components of the car, the front brakes have been the most interesting and yet untouched components on the car. At first, I had no issues with the brakes. Stopping power was plentiful and I never had an issue with overheating. Slowly, as I got braver and drove closer to the car's limit, I found that the brakes were not lasting. It got to the point where the front pads would not last a full 5 20 minute sessions at Motor Sports Ranch Houston.
The traditional upgrades to remediate this issues are:
1: Brake ducts using stock fog lamp locations to run a hose to dedicated plates that replace the factory dust shield for the front brakes.
Picture courtesy of https://www.good-win-racing.com/Mazda-Performance-Part/61-0227.html
2: Big brake upgrade. This is self explanatory and is sometimes paired with ducting as stated in 1.
My approach was something a little different. I had sealed off my fog light holes with Forged Carbon Fog Light Covers/Deletes from Ready Limited. I wanted to pull air from another area of the car. The factory brake dust shields offer little in the way of breathing area for the brake disks. More than 60% of the available area to draw in air is blocked, unlike other manufacturers who have their more open for optimal cooling. I decided to cut up the factory dust shields.
After a lot of thought, I decided to experiment with NACA Ducts from Ready Limited pulling air from under the car while potentially adding downforce to the front of the car. These are a very simple but also not so simple modifications.
The dust shields had to be cut using a cut off wheel and carefully cutting out the areas where the disk draws air into. I kept some of the parts attached and folded them back creating an ramp for air to naturally be drawn into. After that was complete, I took to the inner fender liner forward of the front tires and cut out the silhouette of the duct into the liner. It is positioned in such a way as to pull air that naturally flows under the front bumper and aim it toward the area of the inner wheel and suspension.
After one day with 4-20 minute sessions, I found that with a cheap set of pads, rather than being completely worn, there was more than 60% of the pad remaining, though the cheap compound could not handle the heat. The rotors and pads were in better condition than prior track days and the braking power never faded.
Unfortunately I have no temperature data, the only data I have is what I could directly feel. I will be adding a bracket/scoop which will attach to the lower control arm to guide air into the area of the disk and wheel bearing.
DISCLOSURE: I purchased all these items with my own money and the company had no prior knowledge to this promotion. All opinions are my own. I am affiliated with this company but I do not make a commission on any purchase you make through my link(s).
Photos taken by V Michel Buck